I have no problem with the death penalty per se, but like you am against it...I think the chances of someone innocent being executed are too high to justify it...
That said, if there were some way to eliminate that possibility, I'd be all for it. Either way, these scumbags need to go away for life, with no possibility of parole.
Then you must also choose never to fly in an airplance until the chances of a crash are eliminated? Or perhaps never to drive your car until the chances of death in an automobile accident are also eliminated?